Recently, development has been provided for such a delivery system that content data (title), such as a movie, is stored in a server on the Internet, that the content data is delivered to a user, and that the user records the delivered content data onto an optical disc. In particular, considering that the content data to be delivered is a movie or the like the user does not have to edit in many cases, development has been provided for such a delivery system that the content data is stored on the server in accordance with the DVD-Video standard, which adopts the CSS encryption method (i.e. that the content data is stored on the server in substantially the same condition as that it is recorded on a DVD-ROM, which is a dual-layer, read-only recording medium), before the content data is delivered. Moreover, considering that the content data that has been released recently has increased in size, it is realistic to develop a delivery system that can deliver the content data to be recorded onto the dual-layer DVD-ROM.
Therefore, in order to record the delivered content data, the user needs to provide a dual-layer, recordable recording medium (e.g. a dual-layer DVD-R) or the like. Incidentally, as for dual-layer recording, patent documents 1 and 2 disclose basic technologies.    Patent document 1: Japanese Patent Application Laid Open No. 2006-19019    Patent document 2: Japanese Patent Application Laid Open No. 2007-510251